tests/functional: add tuxrun kvm gdb test for s390x

As with x86_64 we now have the bits to add a KVM gdb test. A couple of
minor wrinkles need to be handled.

The first is applying an offset when loading the symbols to take into
account the relocation that happens.

The other minor wrinkle is the s390x only supports WP_WRITE watch
points so we skip the other watch point tests lest we get confusing
messages about failing to insert HW breakpoints.

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-ID: <20261019192704.3220373-20-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

tests/functional/gdb-scripts/kernel_gdb_test.py

@@ -95,11 +95,13 @@ def do_one_watch(sym, wtype, text):
 def check_watches(sym_name):
     "Watch a symbol for any access."
 
-    # Should hit for any read
-    do_one_watch(sym_name, gdb.WP_ACCESS, "awatch")
+    # s390 only supports write watchpoints
+    if "s390" not in gdb.selected_frame().architecture().name():
+        # Should hit for any read
+        do_one_watch(sym_name, gdb.WP_ACCESS, "awatch")
 
-    # Again should hit for reads
-    do_one_watch(sym_name, gdb.WP_READ, "rwatch")
+        # Again should hit for reads
+        do_one_watch(sym_name, gdb.WP_READ, "rwatch")
 
     # Finally when it is written
     do_one_watch(sym_name, gdb.WP_WRITE, "watch")

tests/functional/qemu_test/tuxruntest.py

@@ -160,6 +160,7 @@ class TuxRunBaselineTest(QemuSystemTest):
                           rootfs_asset,
                           accel=None,
                           dtb_asset=None,
+                          symbol_off = None,
                           drive="virtio-blk-device",
                           console_index=0):
         """
@@ -205,6 +206,9 @@ class TuxRunBaselineTest(QemuSystemTest):
             "--gdb", gdb_path,
         ]
 
+        if symbol_off is not None:
+            cmd.extend(["--symbol-offset", f"{symbol_off}"])
+
         log_cmd = " ".join(f'"{arg}"' if ' ' in arg else arg for arg in cmd)
         self.log.info(f"run-test: {log_cmd}")
 

tests/functional/s390x/test_tuxrun.py

@@ -11,7 +11,7 @@
 #
 # SPDX-License-Identifier: GPL-2.0-or-later
 
-from qemu_test import Asset
+from qemu_test import Asset, skipIfMissingEnv
 from qemu_test.tuxruntest import TuxRunBaselineTest
 
 class TuxRunS390xTest(TuxRunBaselineTest):
@@ -19,6 +19,9 @@ class TuxRunS390xTest(TuxRunBaselineTest):
     ASSET_S390X_KERNEL = Asset(
         'https://storage.tuxboot.com/kernels/6.18.54/s390/bzImage',
         '5efeb31754b211440e1595ab11355bb006fe78a2c0604ed0a8c55c4598b71aec')
+    ASSET_S390X_VMLINUX = Asset(
+        'https://storage.tuxboot.com/kernels/6.18.54/s390/vmlinux.xz',
+        '5bbd4d34e0950f88053a9bfd16078896df4b1ee1696fc2ad62488e681a6bdd8e')
     ASSET_S390X_ROOTFS = Asset(
         'https://storage.tuxboot.com/buildroot/20260924/s390/rootfs.ext4.zst',
         '5ba18c4d18831c50a0c743990f7bdee1d3b520629d423c55b668d8fbbac9c6f5')
@@ -42,5 +45,18 @@ class TuxRunS390xTest(TuxRunBaselineTest):
                            haltmsg="Requesting system halt",
                            accel="kvm")
 
+    @skipIfMissingEnv("QEMU_TEST_GDB")
+    def test_s390_kvm_gdb(self):
+        self.set_machine('s390-ccw-virtio')
+        self.require_accelerator('kvm')
+        self.wait_for_shutdown=False
+        self.common_tuxrun_gdb(kernel_asset=self.ASSET_S390X_KERNEL,
+                               vmlinux_asset=self.ASSET_S390X_VMLINUX,
+                               rootfs_asset=self.ASSET_S390X_ROOTFS,
+                               symbol_off="0x3ffe0000000",
+                               drive="virtio-blk-ccw",
+                               haltmsg="Requesting system halt",
+                               accel="kvm")
+
 if __name__ == '__main__':
     TuxRunBaselineTest.main()

tests/guest-debug/run-test.py

@@ -28,6 +28,7 @@ def get_args():
     parser.add_argument("--kargs", help="Kernel args to --append")
     parser.add_argument("--binary", help="Binary to debug")
     parser.add_argument("--symbols", help="Symbol file for binary to debug")
+    parser.add_argument("--symbol-offset", help="offset to apply to symbols")
     parser.add_argument("--test", help="GDB test script")
     parser.add_argument('test_args', nargs='*',
                         help="Additional args for GDB test script. "
@@ -134,7 +135,11 @@ if __name__ == '__main__':
     gdb_cmd.extend(["-ex", f"target remote {socket_name}"])
 
     if args.symbols:
-        gdb_cmd.extend(["-ex", f"symbol-file {args.symbols}"])
+        sym_arg = f"symbol-file {args.symbols}"
+        if args.symbol_offset:
+            sym_arg += f" -o {args.symbol_offset}"
+
+        gdb_cmd.extend(["-ex", sym_arg])
 
     # finally the test script itself
     if args.test: